This invention is directed to an apparatus for teaching and developing a familiarity with arterial systems and for teaching and developing the association between three dimensional arterial systems and their two dimensional projections as seen in radiographic studies, i.e. in coronary arteriograms.
Routine diagnostic coronary arteriograms are made by the technique of selectively catheterizing the ostium of the right or left coronary artery, injecting radiopaque contrast material, and photographing the dynamic, transient, opacification of each artery, employing image intensification and high speed cinefluorography. A video display device is used to monitor the coronary arteriograms as they are being made.
Presently, students are prepared for making and studying coronary arteriograms by familiarizing the students with locally prepared two dimensional diagrams and drawings, rather than with a display which provides immediate conversion between a three dimensional object and a two dimensional simulated radiographic view which resembles geometrically the coronary arteriograms and the video display image seen when making such arteriograms.
Simulated heart deformities have been displayed in the past by a Flurodemonstrator device which included unenclosed rotatable three dimensional solid models of hearts with stubs of great vessels attached en masse with models of the trachea, aorta, pulmonary arteries, esophagus, and spine incorporating as a radiopaque totality a model of the mediastinum and its contained organs and structures, as would present associated shadows on fluoroscopic examination of the heart. Fluorescent lights illuminated the model for three dimensional viewing, and a shadow of the model was automatically projected on a screen for simulated fluoroscopic two dimensional study. These devices, however, required a darkened room due to the unenclosed location of the model, and they were incapable of use in preparing students for radiographic studies of the arterial systems, as they did not include the arterial branches, and furthermore would cast a large block shadow rather than that of a branching arterial tree.
According to this invention, a three dimensional model of an arterial system is positioned in a housing which is substantially closed to exterior light except for minor ventilation openings if needed, and an observation opening through which the model is visible. A rear-lighted porjection screen is movable from an inoperative position removed from the observation opening to an operative position which lies across the observation opening. When the projection screen is in its operative position, a rear-lighting means in the housing is directed against the rear of the model to cast a shadow thereof on the projection screen.